Method of pasteurizing milk.



H.`FELDMEIER'& Cn B. DALELL. METHOD 0F `PAS'flUmZlNG MILK.

APPLlcAnoN FILED JUNE s, 1911.

Patented May 4, 1915.v

4SHEETs-SHEET 1.

H. `FELDIVIEHR & C. B.- DALZELL.

METHOD 0F PASTEURIZING MILK.

APPLICATION FILED JUNE 9,-19II.

Patentedv May 4, 191:1

H. FELDMEIER & C. B. DALZELL.

METHOD 0F PASTEURIZING MILK.

APPLICATIGN FILED JUNE 9| 1911 Patented May 4, 1915 4 SHEETS-SHEET 4 /7/Q. P i

for l@ya erratas ramena oratori.

HARFEY FELDMEIER AND CHARLES B. DAIAZEI'IL, OF LITTLE FALLS, NEW YGRB.,lASSIGrNORS TO D. H. BUBRELL 92: COMPANY, OF LITTLE FALLS, NEW YORK,

METHOD 0F PASTEURIZING- MILK.

alsace?.

Specicatonvof Letters Patent.

Patented May a, reis.

Application led .Tune 9, 1911. VSerial No. 632,127.

To all 107mm, t may concern:

Be it known that we, HARVEY FELDMELER and CHARLES B. DALZELL, citizens'of the United States, residing at Little Falls, in

the county of Herkimer and Stateof New.-

effect, usually from 20 to 30 minutes, andl then cooling the liquid tothe temperature suitable for filling the same in bottles or othervessels or containers, usually about 400 F.

Heretofore in pasteurizing milk the holding of the milk at thepasteurizing temperature has been elfected invaiious ways whichpermitted the milk to pass through the heater and the cooler withoutinterrupting 'the flow through theseparts ofthe apparatus, but in all ofthese known methods the holding is effected in such a way that the milkcomes toa state of rest,either wholly or in part, as for instance, bycausing the heated milk to collect in a vat or tank in which the milkremains to a greater or less extent during the pasteurizing'period, orby causingv the milk to collect in compartments which are .successivelyfilled and emptied.

The object of this invention is to provide a simple method of holdingthe heated milk or other liquid for the desired length of time in suchmanner that lall vparticles oit the heated liquid are held practicallyfor the same length of time, so that no part of the liquid is allowed toescape before that period has expired or is held beyond that period, andwithout allowing any portion of the liquid to come to a state of rest.To thatl end the heated vliquid is caused to `flow through a holderformed by a sinuous passage, coil or tube .in which the liquid isconfined in the form of a uniformly flowing stream, and thevelocity ofthe liow is s0 regulated that the speed of the liquid in flowing throughthe holder occupies the length of time during which the liquidisrequired to lbe held at the pasteurizing temperature and does not dropbelow a miniaerator of this apparatus.

mum speed which is' suhcient to cause.v the maintenance of a movingstream in which all particles move forwardly with the saine speed andin. which, therefore, neither eddiescounter currents or stagnant bodiesare formed which would retard the movement of the liquid, noraccelerated secondary currents which would cause part of the liquid toflow through the holder in less time than the desired period.

rIhe accompanying drawings, consisting of four sheets, represent twodi-ferent styles of apparatus by which the method can be `practised.InQthe apparatus represented in Figures 144,: which is preferred,'atubular.

holder is empioyed, while in the apparatus represented in Figs. 5-8 theholder is composed-of three superposed sections, each having a flowpassage having the form of a sinuous channel.

' Fig. 1 is a diagrammatic elevation of a ypasteurizing apparatuscomprisin ga tubular holder. holder. cooler.

Fig. 2 is a top plan view .of the Fig. 3 is a side elevation ofthe Fig.4 1s a fragmentary verticall section of .the heateuor cooler, onranenlarged scale. Fig.'5 is a diagrammatic sectional elevation of apasteurizing apparatus comprising a channel holder. Fig. 6- is avertical longitudinal section of the channel holder. same with the coverremoved. Fig. 8 is an elevation of the preliminary heater and Likereference characters refer to like parts in the several figures.

Each apparatus is herein described as be-.

ing used for treating milk.

Referringto Figs. 1 4, A represents the receptacle or tank for the milkto be pasteurized, from which the milk is supplied by a pump 10 or othersuitable means to the heater B which may be composed of two sections 11and 12 which are arranged side by sidev and through `which the milkflows suc- Fig. 7 is a top plan vview of the cessively. This heater ispreferablycomposed of connected internal tubes 13 through which the milkflows and outer tubes 14 headers in the opposite direction to the flowof the milk. C represents the tubular holder or holding coil whichreceives the heated milk, preferably at its upper end, from the heater Bby a pipe 16 and from which of the heater, so that the lvelocity of flowis considerably less in the holder than in the heater. An internalVdiameter of about linches is suitable for the milk flow pipe of the.heater and an internal diameter of 5% inches is suitable for theholder.

It has been'found in practice that a speed of not lessthan eight feetper minute in the holder causes the milk to flow through the same in asolid stream or moving' body in which all particles of themilk flowforwardly with'practically the same speed, so

that neither eddies, cross 'currents or stag nant bodies nor acceleratedsecondary currents are formed and all of the liquid particles consumepractically the same time in passing from the inlet to the outlet of theholder. If the speed is vtoo slow the outermost portions ofthe liquidare greatly re-k tarded and accelerated secondary currents are formed inthe inner portion of the liquid which travel at a much greater speedthan the rest of the liquid and reach the outlet in much less time, sothat the liquid which forms these accelerated currents' is n ot held atthe pasteurizing temperature for the desired length of time, whileotherportions of the liquid are held much longer lthan the desiredperiod, whereby a uniform action of the heat on the liquid is renderedimpossible and the successful operation of the apparatus is defeated.The holder is made of such length that the milk occupies the desiredperiod of time in passing from the inlet to the outlet' of the holder.For illustration, if it is desired to hold the milk for feetper minute,the length 'of the passage should be three hundred and sixty feet. Thespeed of the flow through the heater and the cooler is proportionatelygreater, Awhich is desirable as it promotes the 'exchange of heatbetween the milk and the heating or cooling medium, while reducing thevsize of the apparatus. p

In an apparatus having the preferred proportions herein shown anddescribed and at a speed of about eight feet per minute in the holder,the speed of the milk through the heater will be about 128 feet perminute or holder will be about twenty minutes.

about 16 times the speed through the holder.

The time occupied by the milk in passi-ng through the heater wouldbe `inpractice about one minute and a quarter and the time occupied by themilk in passing through Tte e small diameter of the heating pipesenables the milk to absorb heat more quickly from a heating medium of agiven temperature than if larger pipes were used, while on the otherhand the relatively large diameter of the holder pipes favors theholding of the milk at the pasteurizing temperature without ma-.terial'loss of heat while flowing through the holder. By the use of thepipes of relatively small diameter in the heater it is possible to heatthe milk to the pasteurizing temperature quickly as compared with thetime during which the milk isretained at the -pasteurizing temperaturein the holder. This is desirable because in being heated from about 45F. to about 145 F. the milk passes through a rangeof temperature whichis most 'favorable to the propagation of bacteria, whichrange is fromabout F. to 103 F. The quicker the milk passes through this range oftemperature the less chance there is for the propagation of bac,

teria during the heating process.

D representsthe cooler -to which the milk passes from the holder throughthe pipe 17 and in which the milk is cooled to the temperature suitablefor ,bottling or storing. This cooler is constructed preferably like theheater of connected internal tubes and outer tubes connected by headersand is arranged in several sections 20, 21, 22, 23, side by side, someof which may be cooled by ice water and others by brine. The milk passesfrom the last section 23 to a suitable receiving tank E whichv may bethe tank of the bottle filler. A

`In the operation of this apparatus the cold milk, having a temperatureof about 60 F.,

` is heated in iiowing through the heaterB to the desired pasteurizi'ngtemperature, usually from 140"v to'150 F., and passes with thistemperature to and through the tubular holder in vwhich thisztemperatureis practically maintainedwhile .the milk flows through theholder, themilk losing but a few degrees intemperature as the holder is suitablyyinsulated or protected against loss of heat. `In 'starting theapparatus the discharge cock 24 at the tail end of the holding coil iskept closed until the holder has been filled and the milk is-supplied tothe coil with such speed that in lling the coil the period of time isoccupied which is required i for pasteurization, say thirty minutes.When the holder is fullA the discharge cock isv opened.and thereafterthe milk flows through the holder with` such speed that each'milkparticle occupiesfthe desired holll ing period in flowing v:from 'theinlet to the outlet of the holding coil. The time during which the milkis required to be held at the pasteurizing temperature varies somewhatwith the temperature' which is employed; For illustration, with atemperature of 140D F. a holding period of thirty minutes isisthoroughly and uniformly acted upon..

The milk can be forced through the entire apparatus, heater, holder andcooler, by a single pump'or by gravity, since all of these parts form asingle tubular vpassage through whichthe milk flows without interruptionor comingv to a state of rest and through which the milk can be causedto flow ata predetermined speechk The apparatus is simple andefficient-and contains no moving parts.

If desired, all of the parts of the apparatus pipe 30, or otherwise, andfrom which the milk is drawn by a pipe 31. G represents a m'elimmaryheater and aerator which compr1ses a horizontalfeed trough 32, a heatingand 'aerat'ing coil 33 arranged beneath the same. and a receiving trough34 below the coil. The milk passes from the pipe 31 into `the receivingtrough 32, flows from the latter lupon the upper part of the aeratingandv heating coil 33, descends on the outer side of the coil in a filmor thin sheet and in doing so becomes heated to a certain eX- tent andgives off its odors, vapors or gases and collects in the lower trough34. H represents the finalheater which receives the milk from the trough34 and which completes theheating of the milk to the pasteurizingtemperature. 35 represents a pump which is employed, if necessary, forremoving the milk from the'ltrough 34 and forcing it through thisheater. The latter'consists preferably of an inner coil or pipe throughwhich the milk flowsand outer or surround- 'ing tubes or passages towhich steam or hot water is supplied. I represents the holder whichreceives the heated milk from the iinal heater H by a pipe 36 and whichcomprises a flow passage for the milk of such length that the milk inpassing through the same occupies the period of time which is necessaryfor.

sinuous trough or flow passage 40 and each upper section discharging themilk from the delivery end of its trough or passage into the receivingend of the next lower section. The top section isclosed by a cover 41and each upper section forms a cover for the section next below. Themilk flows from the discharge end of the holder I through a pipe 42 tothe lower end of the coil 33 of the preliminary heater and aerator Gr,flows up-` wardly through said coil and escapes from the upper endthereof through a pipe-43 through which the milk flows to the cooler K.ln passingvthrough the coil 33 the hot milk gives ofl part of Vits heatto the cold milk which flows downwardly over the outer side of the coil,and this heat is so recovered and utilized for partially heating theincoming cold milk, while the hot milk is partially cooled by thisregenerating operation. .Th'ecooler K consists preferably of an innercoil or pipe through which the milk flows, and outer or inclosing tubesor pipes through which the cooling medium flows.

L represents the storage tank or vat which receives rthe pastcurizedmilk by a pipe 46 and in which the milk is sto-red until it is bottledor otherwise disposed of.

In the operation of this apparatus the milkis first heated in a film orthin sheet, while exposed to the air, whereby objectionable odors,vapors and gases are driven ofll and the milk is then heated in thefinal heater, held at the temperature so produced while flowing throughthe channel holder, andL cooled in passing through? the cooler, and thetreatment of the milk with the eX- ception of thepreliminary heating andaerating takes place while lthe milk flows through a closed passage,whereby the milk is prevented fromfabsorl'iing again odors, vapors,germs or bacteria from the surrounding air. .ln referring herein to milkwe intend to include also other similar liquids, for instance, cream,skimmilk, buttermilk, &c. The process can alsobeemployed for thepasteurization or' sterilization of other liquids, for instance, beer orwater.

The tubular holder first described is prei yferredfor several reasonsas-it lis simpler and stronger than the channel holder and can bedrained withoutV difliculty, and becauseitforms with the heater andcooler a continuous liquid-tight passage through which the lliquid canbe forced by a pump or by gravity. The vmilk or other liquid flowsthrough the channel holder in a solid moving body or stream in which allparticles move forwardly practically with the same speed,l and in thatrespect there is no 'substantial difference between the channel holderand the tubular holder. Either apparatusmay be' provided with theregenerating means disclosed by Patent No. 972,608, October 11, 1910.

ing the liquid to the pasteurizing temperature by subjecting the liquidWhile flowing in a' continuous stream .to the influence of a heatingmedium," then removing the liquid from the influence of such medium, andholding the liquid at the pasteurizing temperature for'the requiredperiod of time while.

flowing ina conlined and continuous stream, andthen cooling theliquidwhile flowing in a continuous stream, substantially as set forth.f

2. In the process of pasteuriz-ation, the

-..herein described steps which consist in heating the liquid to thepasteurizing temperature by subjecting the liquid tothe inliuence. orv aheating medium, then removing the I liquid fromthe influence of suchmedium and holding the liquid practically at the pasteurizin temperaturelfor the required period-of time while flowing' inv a confined streamwith a speed which causes all liquid particles to move forwardly withpractically f the same speed throughout the cross 'seotional area of theflowing stream, substan-r tially as set forth.

3.. In the process of pasteurizing milk, the

herein described steps which consist in heating the milk to thepasteurizing temperature by subjecting the milk to the influence of aheating medium. while flowing in a continnous stream, then removing thelmilk from the influence. of such'medum and holding the milk iatthe'pasteurizing temperature for the required length of time whileiowing in a conined and continuous stream at a speed which is greatlyreduced as compared with the speed of the' vmilkv while it is beingheated, and then cooling the milk while flowing in a Icontinuous stream,l

4. In the process of pasteurizing milk, the herein described steps whichconsist in Vheating lthe milk to the pasteurizing temperature bysubjecting the milk tothe inuence of a heating medium while flowingrelatively rapidly in a continuous stream having a relatively smallcross-sectional area, then removing the milk. from the influence of suchheating medium and holding the milk at the pasteurizing temperature forthe required length' of time while flowing in a confined and continuousstream of relatively large iuence of said medium and holding it at thevpasteurizing temperature while flowing in -Y and thencooling the milkwhile flowing in a continuous stream.` Witness our hands in the presenceof two subscribing witnesses'.

' HARVEY FELDMEIER.

- CHARLES B'. DALZELL.

Witnesses:v

' GRIFFITH PRIGHARD, CELIA WooDARD.

a continuous stream'of relatively large crosssectional area at a greatlyreduced speed,

